Needling loops into carrier sheets

ABSTRACT

A sheet-form loop product includes a flexible paper substrate and a layer of staple fibers disposed on a first side of the substrate, exposed loops of the fibers extending from holes through the substrate to a second side of the substrate, with bases of the loops being anchored on the first side of the substrate. The loops can be fastening loops. The product is formed by needling the fibers through the paper and then bonding the fibers. Examples include loop fastener materials, towels, abrasive scrubbing pads and sanding materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of, and claimspriority under 35 U.S.C. §120 to, U.S. Application Ser. No. 10/728,138,filed on Dec. 3, 2003, now U.S. Pat. No. 7,156,937, and also claimspriority under 35 U.S.C. §119(e) to U.S. provisional application60/430,731, filed on Dec. 3, 2002. The entire contents of both of thesepriority applications are incorporated herein by reference, as if setforth in their entirety.

TECHNICAL FIELD

This invention relates to methods of making sheet-form loop products,particularly by needling fibers into carrier sheets to form loops, andproducts produced thereby.

BACKGROUND

Touch fasteners are particularly desirable as fastening systems forlightweight, disposable garments, such as diapers. In an effort toprovide a cost-effective loop material, some have recommended variousalternatives to weaving or knitting, such as by needling a lightweightlayer of fibers to form a light non-woven material that can then bestretched to achieve even lighter basis weight and cost efficiency, withthe loop structures anchored by various binding methods, andsubsequently adhered to a substrate. U.S. Pat. No. 6,329,016 teaches onesuch method, for example.

Materials with lower unit costs and better performance are desired.Reducing fiber content can lower cost, but can also affect overallperformance or load-carrying capacity of the loop material, as well asthe dimensional stability and handling efficiency of the loop product.Also, choice of fiber material is often compromised by a need for theloop material to be weld-compatible with a substrate (e.g., an outerlayer of a diaper) to which the loop material is to be permanentlybonded.

Various methods of bonding fibers to underlying substrates have alsobeen taught, for forming touch fasteners and other loop-bearingmaterials.

SUMMARY

In one aspect of the invention, a method of making a sheet-form loopproduct includes: placing a layer of staple fibers against a first sideof a flexible paper substrate; needling fibers of the layer through thepaper substrate by piercing the substrate with needles that dragportions of the fibers through holes formed in the paper substrateduring needling, leaving exposed loops of the fibers extending from theholes on a second side of the paper substrate; and anchoring fibersforming the loops.

By “paper” we mean flexible sheet-form products made of wood pulp, orsynthetic materials formulated to have functional properties essentiallythe same as those of paper made of wood pulp. It includes a broad rangeof types of papers, including tissue papers, construction papers, typingpaper, newsprint, packaging papers, and others.

In another aspect of the invention, a sheet-form loop product includes:a flexible substrate having a plurality of holes pierced therethrough;and a layer of staple fibers disposed on a first side of the substrate,exposed loops of the fibers extending from the holes on a second side ofthe substrate, with bases of the loops being anchored on the first sideof the substrate; wherein the substrate comprises paper.

In embodiments of the method, anchoring the fibers can include fusingthe fibers on the first side of the substrate to anchor the loops. Insome cases, the method also includes heating the fibers from the firstside of the substrate prior to fusing. In some cases, the method alsoincludes carding and cross-lapping the fibers prior to disposing thefibers on the substrate.

Anchoring the fibers to the substrate can include laminating the fibersto the substrate by pressing the fibers against the substrate employinga bed of discrete pins that apply pressure to the substrate only atdiscrete points corresponding to the pins. In some embodiments featuringlaminating the fibers to the substrate, the fibers are loose andunconnected to the substrate until laminated. In some cases, theanchoring occurs subsequent to needling.

In some embodiments, the needling includes at least 40 piercings persquare centimeter, preferably 60 to 100 piercings per square centimeter.

In some embodiments, the fibers are fused to one another. Moreparticularly, in some cases, the fibers are fused on the first side ofthe substrate and/or are fused directly to one another.

In some embodiments, the fibers include bicomponent fibers having a coreof one material and a sheath of another material, and anchoring thefibers can include melting material of the sheaths of the bicomponentfibers to bind fibers together. In some embodiments with bicomponentfibers, the bicomponent fibers make up only between about 15 and 30percent of the fibers, by weight.

For touch fastener applications, needling fibers of the layer throughthe paper substrate and anchoring fibers forming the loops forms loopssized and constructed to be releasably engageable by a field of hooksfor hook-and-loop fastening. The fibers preferably have a strength of atleast 10 grams and are of a denier of no more than about 6.

In some embodiments of the loop product, the bases of the fibers areanchored at discrete bond points between the holes. In some of theseembodiments, the fibers are loose and unconnected except at the bondpoints.

In some embodiments, the staple fibers are disposed on the substrate ina layer of a total fiber weight of less than about 2 ounces per squareyard (67 grams per square meter) (e.g. in a layer of a total fiberweight of no more than about one ounce per square yard (34 grams persquare meter)). In some cases, the staple fibers are disposed on thesubstrate in a carded, unbonded state.

In some embodiments, the loop product has an overall weight of less thanabout 5 ounces per square yard (167 grams per square meter).

In some embodiments, the holes have a distribution with an overall holedensity of more than about 60 holes per square centimeter.

In some embodiments of the loop product, the loops are hook-engageableand the product is a loop fastener product. In some of theseembodiments, the loops are formed primarily of fibers having anindividual fiber strength of at least 8 grams.

In some cases, the loop product, in a continuous length, is spooled intoroll form.

In another aspect of the invention, a disposable towel includes: a sheetof paper having a plurality of holes pierced therethrough; and a layerof staple fibers disposed on a first side of the paper, loops of thefibers extending from the holes on a second side of the paper, withbases of the loops being anchored on the first side of the paper.

In another aspect of the invention, an abrasive scrubbing materialincludes: a sheet of flexible material having a plurality of holespierced therethrough; and a layer of staple abrasive fibers disposed ona first side of the flexible material, loops of the fibers extendingfrom the holes on a second side of the flexible material to form ascrubbing surface, with bases of the loops being anchored on the firstside of the flexible material. Some embodiments of this aspect of theinvention include emery fibers. Some embodiments of this aspect of theinvention feature steel fibers.

In another aspect of the invention an abrasive sanding materialincludes: a sheet of flexible material having a plurality of holespierced therethrough; and a layer of staple fibers disposed on a firstside of the flexible material, loops of the fibers extending from theholes on a second side of the flexible material to form a fasteningsurface, with bases of the loops being anchored on the first side of theflexible material. Abrasive material is disposed on an opposite side ofthe flexible material and arranged to be exposed for sanding with thesanding material releasably attached to a support by its fasteningsurface.

In some cases, the abrasive material is a field of abrasive particlesbonded to the flexible material. In some other cases, the fibers arefine metal filaments, such as steel wook, and the abrasive material isportions of such fibers exposed on the opposite side of the flexiblematerial.

With respect to those aspects of the invention featuring papersubstrates, we have found paper to be quite suitable for supporting aloose, unconnected layer of carded staple fibers prior to and duringneedling, and to sufficiently survive fairly dense needling so as toretain many useful properties in the finished product. Even needled,paper substrates can bond readily to polyethylene film, for example, orto many other materials. Paper can enable substantial heating andmelting of fibers remaining on the side opposite the loops withoutdegrading the loops. Paper can be pre-printed before needling, withprinted images remaining clearly visible even after needling. For paperproducts exposed to water, such as disposable paper towels, needlingstaple polymer fibers into the towel can greatly improve the strength ofthe towel when wet, as the fiber web formed by needling, especiallyafter bonding, maintains some dimensional stability when the underlyingpaper substrate is thoroughly soaked.

Similarly, the methods disclosed herein can form very lightweightfastener materials and materials of other functional uses, such asabrasive or scrubbing materials, for example. The method enables the useof a very sparse amount of fibers, as compared, for example, tonon-woven materials formed exclusively of fibers, as the dimensionalstability of the overall product need not be established solely by fiberentanglement, as it is aided by the presence of the substrate. Indeed, agreat proportion of the fibers can be inexpensively formed into loopsexposed at the functional surface of the sheet-form product, whether forfastening or other purposes. As the material cost of such high-tenacityfibers can be a substantial part of the overall cost of such products,the more efficient use of fiber is a substantial savings.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagrammatic view of a process for forming loop material.

FIGS. 2A-2D are diagrammatic side views of stages of a needling step ofthe process of FIG. 1. FIG. 2E is a diagrammatic side view showing anelliptical path that may be followed by the needle during needling.

FIG. 3 is an enlarged diagrammatic view of a lamination nip throughwhich the loop material passes during the process of FIG. 1.

FIG. 4 is a highly enlarged diagrammatic view of a loop structure formedby needling with fork needles through film.

FIG. 4A is an enlarged photograph of a rolled edge of a loop productformed by needling with fork needles through film, showing severaldiscrete loop structures.

FIG. 4B is a highly enlarged photograph of one of the loop structuresshown in FIG. 4A.

FIG. 4C illustrates a loop structure formed by needling with crownneedles through polyester film.

FIG. 5 is a diagrammatic view showing an alternative lamination steputilizing a powder-form binder.

FIG. 6 is a highly enlarged diagrammatic view of a loop materialaccording to an embodiment in which the carrier film is substantiallydisintegrated during needling.

FIG. 7 is a photo of a loop material having an embossed pattern on itsloop-carrying surface.

FIG. 7A is an enlarged view of one of the embossing cells, containingmultiple discrete loop structures.

FIG. 7B is a highly enlarged diagrammatic view of an embossed loopmaterial having convex regions.

FIG. 8 is a diagrammatic view of a process for forming a loop materialhaving discrete regions of loop while removing non-needled fibers fromthe carrier web.

FIG. 9 is a diagrammatic view of a process for rendering needledportions of a loop product substantially fluid-impermeable.

FIG. 10 shows a loop product consisting essentially of a sheet of paperand fibers that have been needled through the paper.

FIG. 11 is a partial perspective view of a cut corner of a corrugatedcardboard, with the product of FIG. 10 serving as one side of thecardboard.

FIG. 12 is a partial perspective view of a scrapbook or photo album withpages formed of the material of FIG. 10.

FIG. 13 is a partial edge view of a sanding disk or sandpaper, with anarray of engageable loops on one side and a field of abrasive particleson the other side.

FIG. 14 is a partial edge view of a sanding disk with fibers forming anarray of engageable loops on one side and an abrasive surface on theother side.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Descriptions of loop products will follow a description of some methodsof making loop products.

FIG. 1 illustrates a machine and process for producing an inexpensivetouch fastener loop product. Beginning at the upper left end of FIG. 1,a carded and cross-lapped layer of fibers 10 is created by two cardingstages with intermediate cross-lapping. Weighed portions of staplefibers of different types are fed to the first carding station 30 by acard feeder 34. Card station 30 includes a 36-inch breast roll 50, a60-inch breaker main 52, and a 50-inch breaker doffer 54. The first cardfeedroll drive includes 3-inch feedrolls 56 and a 3-inch cleaning rollon a 13-inch lickerin roll 58. An 8-inch angle stripper 60 transfers thefiber to breast roll 50. There are three 8-inch worker roll sets 62 onthe breast roll, and a 16-inch breast doffer 64 feeds breaker main 52,against which seven 8-inch worker sets 66 and a flycatcher 68 run. Thecarded fibers are combed onto a conveyer 70 that transfers the singlefiber layer into a cross-lapper 72. Before cross-lapping, the cardedfibers still appear in bands or streaks of single fiber types,corresponding to the fibrous balls fed to carding station 30 from thedifferent feed bins. Cross-lapping, which normally involves a 90-degreereorientation of line direction, overlaps the fiber layer upon itselfand is adjustable to establish the width of fiber layer fed into thesecond carding station 74. In this example, the cross-lapper outputwidth is set to approximately equal the width of the carrier into whichthe fibers will be needled. Cross-lapper 72 may have a lapper apron thattraverses a floor apron in a reciprocating motion. The cross-lapper layscarded webs of, for example, about 80 inches (1.5 meters) width andabout one-half inch (1.3 centimeters) thickness on the floor apron, tobuild up several layers of criss-crossed web to form a layer of, forinstance, about 80 inches (1.5 meters) in width and about 4 inches (10centimeters) in thickness, comprising four double layers of carded web.During carding, the fibers are separated and combed into a cloth-likemat consisting primarily of parallel fibers. With nearly all of itsfibers extending in the carding direction, the mat has some strengthwhen pulled in the carding direction but almost no strength when pulledin the carding cross direction, as cross direction strength results onlyfrom a few entanglements between fibers. During cross-lapping, thecarded fiber mat is laid in an overlapping zigzag pattern, creating amat 10 of multiple layers of alternating diagonal fibers. The diagonallayers, which extend in the carding cross direction, extend more acrossthe apron than they extend along its length.

Cross-lapping the web before the second carding process provides severaltangible benefits. For example, it enhances the blending of the fibercomposition during the second carding stage. It also allows forrelatively easy adjustment of web width and basis weight, simply bychanging cross-lapping parameters.

Second carding station 74 takes the cross-lapped mat of fibers and cardsthem a second time. The feedroll drive consists of two 3-inch feed rollsand a 3-inch cleaning roll on a 13-inch lickerin 58, feeding a 60-inchmain roll 76 through an 8-inch angle stripper 60. The fibers are workedby six 8-inch worker rolls 78, the last five of which are paired with3-inch strippers. A 50-inch finisher doffer 80 transfers the carded webto a condenser 82 having two 8-inch condenser rolls 84, from which theweb is combed onto a carrier sheet 14 fed from spool 16. The condenserincreases the basis weight of the web from about 0.7 osy (ounce persquare yard) to about 1.0 osy, and reduces the orientation of the fibersto remove directionality in the strength or other properties of thefinished product.

The carrier sheet 14, such as paper, may be supplied as a singlecontinuous length, or as multiple, parallel strips. For particularlywide webs, it may be necessary or cost effective to introduce two ormore parallel sheets, either adjacent or slightly overlapping. Theparallel sheets may be unconnected or joined along a mutual edge. Thecarded, uniformly blended layer of fibers from condenser 82 is carriedup conveyor 86 on carrier sheet 14 and into needling station 18. As thefiber layer enters the needling station, it has no stability other thanwhat may have been imparted by carding and cross-lapping. In otherwords, the fibers are not pre-needled or felted prior to needling intothe carrier sheet. In this state, the fiber layer is not suitable forspooling or accumulating prior to entering the needling station.

In needling station 18, the carrier sheet 14 and fiber areneedle-punched from the fiber side. The needles are guided through astripping plate above the fibers, and draw fibers through the carriersheet 14 to form loops on the opposite side. During needling, thecarrier sheet is supported on a bed of pins or bristles extending from adriven support belt or brush apron 22 that moves with the carrier sheetthrough the needling station. Alternatively, carrier sheet 14 can besupported on a screen or by a standard stitching plate (not shown).Reaction pressure during needling is provided by a stationary reactionplate 24 underlying apron 22. In this example, needling station 18needles the fiber-covered carrier sheet 14 with an overall penetrationdensity of about 80 to 160 punches per square centimeter. At thisneedling density, we have found that 38 gauge forked tufting needleswere small enough to not obliterate the paper, leaving sufficient paperinterconnectivity that the paper continued to exhibit some dimensionalstability within its plane. During needling, the thickness of the cardedfiber layer only decreases by about half, as compared with feltingprocesses in which the fiber layer thickness decreases by one or moreorders of magnitude. As fiber basis weight decreases, needling densitymay need to be increased. The needling station 18 may be a “structuringloom” configured to subject the fibers and carrier web to a randomvelouring process. Thus, the needles penetrate a moving bed of bristlesarranged in an array (brush apron 22). The brush apron may have abristle density of about 2000 to 3000 bristles per square inch (310 to465 bristles per square centimeter), e.g., about 2570 bristles persquare inch (400 per square centimeter). The bristles are each about0.018 inch (0.46 millimeter) in diameter and about 20 millimeters long,and are preferably straight. The bristles may be formed of any suitablematerial, for example 6/12 nylon. Suitable brushes may be purchased fromStratosphere, Inc., a division of Howard Brush Co., and retrofitted ontoDILO and other random velouring looms. Generally, the brush apron movesat the desired line speed.

FIGS. 2A through 2D sequentially illustrate the formation of a loopstructure by needling. As a forked needle enters the fiber mat 10 (FIG.2A), some individual fibers 12 will be captured in the cavity 36 in theforked end of the needle. As needle 34 pierces paper 14 (FIG. 2B), thesecaptured fibers 12 are drawn with the needle through the hole 38 formedin the paper to the other side of the paper. As shown, paper 14 remainsgenerally supported by pins 20 through this process, the penetratingneedle 34 entering a space between adjacent pins. Alternatively, paper14 can be supported by a screen or stitching plate (not shown) thatdefines holes aligned with the needles. As needle 34 continues topenetrate (FIG. 2C), tension is applied to the captured fibers, drawingmat 10 down against paper 14. In this example, a total penetration depth“D_(p)” of about 5.0 millimeters, as measured from the entry surface ofpaper 14, was found to provide a well-formed loop structure withoutoverly stretching fibers in the remaining mat. Excessive penetrationdepth can draw loop-forming fibers from earlier-formed tufts, resultingin a less robust loop field. Penetration depths of 2 and 7 millimetersare also suitable, although the 5.0 millimeter penetration is presentlypreferred. When needle 34 is retracted (FIG. 2D), the portions of thecaptured fibers 12 carried to the opposite side of the carrier webremain in the form of a plurality of individual loops 40 extending froma common trunk 42 trapped in paper hole 38. When film is employed as thecarrier sheet, residual stresses in the film around the hole, acting totry to restore the film to its planar state, can apply a slight pressureto the fibers in the hole, helping to secure the base of the loopstructure. The film can also help to resist tension applied to the fiberremaining on the mat side of the film that would tend to pull the loopsback through the hole. The final loop formation preferably has anoverall height “H_(L)” of about 0.040 to 0.090 inch (1.0 to 2.3millimeters), for engagement with the size of male fastener elementscommonly employed on disposable garments and such.

Advance per stroke is limited due to a number of constraints, includingneedle deflection and potential needle breakage. Thus, it may bedifficult to accommodate increases in line speed and obtain aneconomical throughput by adjusting the advance per stroke. As a result,the holes pierced by the needles may become elongated, due to the travelof the carrier sheet while the needle is interacting with the carriersheet (the “dwell time”). This elongation is generally undesirable, asit reduces the amount of support provided to the base of each of theloop structures by the surrounding substrate, and may adversely affectresistance to loop pull-out. Moreover, this elongation will tend toreduce the mechanical integrity of the carrier film due to excessivedrafting, i.e., stretching of the film in the machine direction andcorresponding shrinkage in the cross-machine direction.

Elongation of the holes may be reduced or eliminated by causing theneedles to travel in a generally elliptical path, viewed from the side.This elliptical path is shown schematically in FIG. 2E. Referring toFIG. 2E, each needle begins at a top “dead” position A, travels downwardto pierce the film (position B) and, while it remains in the film (fromposition B through bottom “dead” position C to position D), movesforward in the machine direction. When the needle has traveled upwardsufficiently for its tip to have exited the pierced opening (positionD), it continues to travel upward, free of the film, while alsoreturning horizontally (opposite to the machine direction) to itsnormal, rest position (position A), completing the elliptical path. Thiselliptical path of the needles is accomplished by moving the entireneedle board simultaneously in both the horizontal and verticaldirections. Needling in this manner is referred to herein as “ellipticalneedling.” Needling looms that perform this function are available fromDILO System Group, Eberbach, Germany, under the tradename “HYPERPUNCHSystems.”

During elliptical needling, the horizontal travel of the needle board ispreferably roughly equivalent to the distance that the film advancesduring the dwell time. The horizontal travel is a function of needlepenetration depth, vertical stroke length, carrier film thickness, andadvance per stroke. Generally, at a given value of needle penetrationand film thickness, horizontal stroke increases with increasing advanceper stroke. At a fixed advance per stroke, the horizontal strokegenerally increases as depth of penetration and web thickness increases.

For example, for a very thin paper having a thickness of 0.013millimeter (so thin that it is not taken into account), a loom outfeedof 18.9 meters per minute, an effective needle density of 15,006needles/meter, a vertical stroke of 35 mm, a needle penetration of 5.0mm, and a headspeed of 2,010 strokes/min, the preferred horizontal throw(i.e., the distance between points B and D in FIG. 2E) would be 3.3 mm,resulting in an advance per stroke of 9.4 mm.

Using elliptical needling, it may be possible to obtain line speeds 30ypm (yards/minute) or mpm (meters/minute) or greater, e.g., 50 ypm ormpm, for example 60 ypm. Such speeds may be obtained with minimalelongation of the holes, for example the length of the holes in themachine direction may be less than 20 percent greater than the width ofthe holes in the cross-machine direction, preferably less than 10percent greater and in some instances less than 5 percent greater.

For needling longitudinally discontinuous regions of the material, suchas to create discrete loop regions as discussed further below, theneedle boards can be populated with needles only in discrete regions,and the needling action paused while the material is indexed through theloom between adjacent loop regions. Effective pausing of the needlingaction can be accomplished by altering the penetration depth of theneedles during needling, including to needling depths at which theneedles do not penetrate the carrier sheet. Such needle looms areavailable from FEHRER AG in Austria, for example. Alternatively, meanscan be implemented to selectively activate smaller banks of needleswithin the loom according to a control sequence that causes the banks tobe activated only when and where loop structures are desired. Lanes ofloops can be formed by a needle loom with lanes of needles separated bywide, needle-free lanes.

In the example illustrated, the needled product 88 leaves needlingstation 18 and brush apron 22 in an unbonded state, and proceeds to alamination station 92. If the needling step was performed with thecarrier sheet supported on a bed of rigid pins, lamination can beperformed with the carrier sheet still carried on the bed of pins. Priorto the lamination station, the web passes over a gamma gage (not shown)that provides a rough measure of the mass per unit area of the web. Thismeasurement can be used as feedback to control the upstream carding andcross-lapping operations. The web is stable enough at this stage to beaccumulated in an accumulator 90 between the needling and laminationstations. As known in the art, accumulator 90 is followed by a spreadingroll (not shown) that spreads and centers the web prior to entering thenext process. Prior to lamination, the web may also pass through acoating station (not shown) in which a binder is applied to enhancelamination. In lamination station 92, the web first passes by one ormore infrared heaters 94 that preheat the fibers and/or carrier sheetfrom the side opposite the loops. In products relying on bicomponentfibers for bonding, heaters 94 preheat and soften the sheaths of thebicomponent fibers. In one example, the heater length and line speed aresuch that the web spends about four seconds in front of the heaters.Just downstream of the heaters is a web temperature sensor (not shown)that provides feedback to the heater control to maintain a desired webexit temperature. For lamination, the heated web is trained about a hotcan 96 against which four idler card cloth-covered rolls 98 of five inch(13 centimeters) solid diameter (excluding the card cloth), and adriven, rubber, card cloth-covered roll 100 of 18 inch (46 centimeters)solid diameter, rotate under controlled pressure. The pins of the cardcloth rolls 98,100 thus press the web against the surface of hot can 96at discrete pressure points, thus bonding the fibers at discretelocations without crushing other fibers, generally between the bondpoints, that remain exposed and open for engagement by hooks. For manymaterials, the bonding pressure between the card cloth rolls and the hotcan is quite low, in the range of 1-10 pounds per square inch (70-700grams per square centimeter) or less. The hot can 96 can have acompliant outer surface, or be in the form of a belt. As an alternativeto roller nips, a flatbed fabric laminator (not shown) can be employedto apply a controlled lamination pressure for a considerable dwell time.Such flatbed laminators are available from Glenro Inc. in Paterson, N.J.In some applications, the finished loop product is passed through acooler (not shown) prior to embossing.

The pins extending from card cloth-covered rolls 98,100 are arranged inan array of rows and columns, with a pin density of about 200 and 350pins per square inch (31 to 54 pins per square centimeter) in a flatstate, preferred to be between about 250 to 300 pins per square inch (39to 47 pins per square centimeter). The pins are each about 0.020 inch(0.5 millimeter) in diameter, and are preferably straight to withstandthe pressure required to laminate the web. The pins extend from abacking about 0.25 inch (6.4 millimeters) in thickness. The backing isof two layers of about equal thickness, the lower layer being of fibrouswebbing and the upper layer being of rubber. The pins extend about 0.25inch (6.4 millimeters) from the rubber side of the backing. Because ofthe curvature of the card cloth rolls, the effective density of the pintips, where lamination occurs, is lower than that of the pins with thecard cloth in a flat state. A flat state pin density of 200 to 350 pinsper square inch (31 to 54 pins per square centimeter) equates to aneffective pin density of only 22 to 38 pins per square centimeter onidler rolls 98, and 28 to 49 pins per square centimeter on driven rubberroll 100. In most cases, it is preferable that the pins not penetratethe carrier sheet during bonding, but that each pin provide sufficientsupport to form a robust bond point between the fibers. In anon-continuous production method, such as for preparing discrete patchesof loop material, a piece of carrier sheet 14 and a section of fiber mat12 may be layered upon a single card cloth, such as are employed forcarding webs, for needling and subsequent bonding, prior to removal fromthe card cloth.

FIG. 3 is an enlarged view of the nip between hot can 96 and one of thecard cloth rolls. As discussed above, due to the curvature of the cardcloth rolls, their pins 102 splay outward, such that the effective pindensity at the hot can is lower than that of the card cloth in a planarstate. The pins contact the carrier sheet (or its remnants, depending onneedling density) and fuse underlying fibers to each other and/or tomaterial of the carrier sheet, forming a rather solid mass 42 of fusedmaterial in the vicinity of the pin tip, and a penumbral area of fusedbut distinct fibers surrounding each pin. The laminating parameters canbe varied to cause these penumbral, partially fused areas to beoverlapped if desired, creating a very strong, dimensionally stable webof fused fibers across the non-working side of the loop product that isstill sufficiently flexible for many uses. Alternatively, the web can belaminated such that the penumbral areas are distinct and separate,creating a looser web. For most applications the fibers should not becontinuously fused into a solid mass across the back of the product, inorder to retain a good hand and working flexibility. The number ofdiscrete fused areas per unit area of the bonded web is such that staplefibers with portions extending through holes to form engageable loops 40that have other portions, such as their ends, secured in one or more ofsuch fused areas 42, such that the fused areas are primarily involved inanchoring the loop fibers against pullout from hook loads. Whether thewelds are discrete points or an interconnected grid, this furthersecures the fibers, helping to strengthen the loop structures 48. Thelaminating occurs while the loop structures 48 are safely disposedbetween pins 102, such that no pressure is applied to crush the loopsduring bonding. Protecting the loop structures during laminationsignificantly improves the performance of the material as a touchfastener, as the loop structures remain extended from the base for hookengagement.

If desired, a backing sheet (not shown) can be introduced between thehot can and the needled web, such that the backing sheet is laminatedover the back surface of the loop product while the fibers are bondedunder pressure from the pins of apron 22.

Referring back to FIG. 1, from lamination station 92 the laminated webmoves through another accumulator 90 to an embossing station 104, wherea desired pattern of locally raised regions is embossed into the webbetween two counter-rotating embossing rolls. In some cases, the web maymove directly from the laminator to the embossing station, withoutaccumulation, so as to take advantage of any latent temperature increasecaused by lamination. The loop side of the bonded loop product isembossed with a desired embossing pattern prior to spooling. In thisexample the loop product is passed through a nip between a drivenembossing roll 54 and a backup roll 56. The embossing roll 54 has apattern of raised areas that permanently crush the loop formationsagainst the carrier sheet, and may even melt a proportion of the fibersin those areas. Embossing may be employed simply to enhance the textureor aesthetic appeal of the final product. In some cases, roll 56 has apattern of raised areas that mesh with dimples in roll 54, such thatembossing results in a pattern of raised hills or convex regions on theloop side, with corresponding concave regions 45 (FIG. 7B) on thenon-working side of the product, such that the embossed product has agreater effective thickness than the pre-embossed product. Additionally,as shown in FIG. 7B, embossing presents the loop structures 48 orotherwise engageable fiber portions at different angles to a matingfield of hooks, for better engagement. More details of a suitableembossing pattern are discussed below with respect to FIGS. 7 and 7A.

The embossed web then moves through a third accumulator 90, past a metaldetector 106 that checks for any broken needles or other metal debris,and then is slit and spooled for storage or shipment. During slitting,edges may be trimmed and removed, as can any undesired carrier sheetoverlap region necessitated by using multiple parallel strips of carriersheet.

We have found that, using the process described above, a useful loopproduct may be formed with relatively little fiber 12. In one example,mat 10 has a basis weight of only about 1.0 osy (33 grams per squaremeter). Fibers 12 are drawn and crimped polyester fibers, 3 to 6 denier,of about a four-inch (10 centimeters) staple length, mixed with crimpedbicomponent polyester fibers of 4 denier and about two-inch (5centimeters) staple length. The ratio of fibers may be, for example, 80percent solid polyester fiber to 20 percent bicomponent fiber. In otherembodiments, the fibers may include 15 to 30 percent bicomponent fibers.The preferred ratio will depend on the composition of the fibers and theprocessing conditions. Generally, too little bicomponent fiber maycompromise loop anchoring, due to insufficient fusing of the fibers,while too much bicomponent fiber will tend to increase cost and mayresult in a stiff product and/or one in which some of the loops areadhered to each other. The bicomponent fibers are core/sheath drawnfibers consisting of a polyester core and a copolyester sheath having asoftening temperature of about 110 degrees Celsius, and are employed tobind the solid polyester fibers to each other and the carrier.

In this example, both types of fibers are of round cross-section and arecrimped at about 7.5 crimps per inch (3 crimps per centimeter). Suitablepolyester fibers are available from INVISTA of Wichita, Kans.,(www.invista.com) under the designation Type 291. Suitable bicomponentfibers are available from INVISTA under the designation Type 254. As analternative to round cross-section fibers, fibers of othercross-sections having angular surface aspects, e.g. fibers of pentagonor pentalobal cross-section, can enhance knot formation during needling.

Loop fibers with tenacity values of at least 2.8 grams per denier havebeen found to provide good closure performance, and fibers with atenacity of at least 5 or more grams per denier (preferably even 8 ormore grams per denier) are even more preferred in many instances. Ingeneral terms for a loop-limited closure, the higher the loop tenacity,the stronger the closure. The polyester fibers of mat 10 are in a drawn,molecular oriented state, having been drawn with a draw ratio of atleast 2:1 (i.e., to at least twice their original length) under coolingconditions that enable molecular orientation to occur, to provide afiber tenacity of about 4.8 grams per denier.

The loop fiber denier should be chosen with the hook size in mind, withlower denier fibers typically selected for use with smaller hooks. Forlow-cycle applications for use with larger hooks (and thereforepreferably larger diameter loop fibers), fibers of lower tenacity orlarger diameter may be employed.

For many applications, particularly products where the hook and loopcomponents will be engaged and disengaged more than once (“cycled”), itis desirable that the loops have relatively high strength so that theydo not break or tear when the fastener product is disengaged. Loopbreakage causes the loop material to have a “fuzzy,” damaged appearance,and widespread breakage can deleteriously effect re-engagement of thefastener.

Loop strength is directly proportional to fiber strength, which is theproduct of tenacity and denier. Fibers having a fiber strength of atleast 6 grams, for example at least 10 grams, provide sufficient loopstrength for many applications. Where higher loop strength is required,the fiber strength may be higher, e.g., at least 15 grams. Strengths inthese ranges may be obtained by using fibers having a tenacity of about2 to 7 grams/denier and a denier of about 1.5 to 5, e.g., 2 to 4. Forexample, a fiber having a tenacity of about 4 grams/denier and a denierof about 3 will have a fiber strength of about 12 grams.

Other factors that affect engagement strength and cycling are thegeometry of the loop structures, the resistance of the loop structuresto pull-out, and the density and uniformity of the loop structures overthe surface area of the loop product. The first two of these factors arediscussed above. The density and uniformity of the loop structures isdetermined in part by the coverage of the fibers on the carrier sheet.In other words, the coverage will affect how many of the needlepenetrations will result in hook-engageable loop structures. Fibercoverage is indicative of the length of fiber per unit area of thecarrier sheet, and is calculated as follows:Fiber coverage (in meters per square meter)=Basis Weight/Denier×9000

Thus, in order to obtain a relatively high fiber coverage at a low basisweight, e.g., less than 33 gsm, it is desirable to use relatively lowdenier (i.e., fine) fibers. However, the use of low denier fibers willrequire that the fibers have a higher tenacity to obtain a given fiberstrength, as discussed above. Higher tenacity fibers are generally moreexpensive than lower tenacity fibers, so the desired strength, cost andweight characteristics of the product must be balanced to determine theappropriate basis weight, fiber tenacity and denier for a particularapplication. It is generally preferred that the fiber layer of the loopproduct have a calculated fiber coverage of at least 50,000, preferablyat least 90,000, and more preferably at least 100,000.

To produce loop materials having a good balance of low cost, lightweight and good performance, it is generally preferred that the basisweight be less than 70 gsm, e.g., 33 to 67 gsm, and the coverage beabout 50,000 to 200,000.

Various synthetic or natural fibers may be employed. In someapplications, wool and cotton may provide sufficient fiber strength.Presently, thermoplastic staple fibers which have substantial tenacityare preferred for making thin, low-cost loop product that has goodclosure performance when paired with very small molded hooks. Forexample, polyolefins (e.g., polypropylene or polyethylene), polyesters(e.g., polyethylene terephthalate), polyamides (e.g., nylon), acrylicsand mixtures, alloys, copolymers and co-extrusions thereof are suitable.Polyester is presently preferred. Fibers having high tenacity and highmelt temperature may be mixed with fibers of a lower melt temperatureresin. For a product having some electrical conductivity, a smallpercentage of metal fibers may be added. For instance, loop products ofup to about 5 to 10 percent fine metal fiber, for example, may beadvantageously employed for grounding or other electrical applications.

The paper carrier sheet 14 may be pre-pasted with an adhesive on thefiber side to help bond the fibers and/or a backing layer to the paper.

Still referring to FIG. 1, in some cases a wire screen is used in placeof both the bed of pins or bristles 20 and driven support belt 22, foran analogous needling process. The wires define openings through whichthe needle passes as it draws fibers 12 through the carrier sheet 14.Suitable screens can be made from materials including bronze, copper,brass, and stainless steel. We have found that screens made of brasswire with a nominal diameter of between about 0.02 and 0.03 inch (0.5and 0.8 millimeter) or, more preferably, between about 0.023 and 0.028inch (0.6 and 0.7 millimeter), are resilient without being too stiff.Screens having openings with a nominal width of between about 0.05 and0.2 inch (1.3 and 5.1 millimeter) or, more preferably, between about0.06 and 0.1 inch (1.5 and 2.5 millimeter) are appropriate for thispurpose. Such screens are available from McMaster-Carr Supply Co. ofElmhurst, Ill. under the designation 9223T41.

FIG. 4 is an enlarged view of a loop structure 48 containing multipleloops 40 extending from a common trunk 43 through a hole in paper 14, asformed by the above-described method. As shown, loops 40 stand proud ofthe underlying paper, available for engagement with a mating hookproduct, due at least in part to the vertical stiffness of trunk 43 ofeach formation, which is provided by the anchoring of the fibers to eachother and the paper. This vertical stiffness acts to resist permanentcrushing or flattening of the loop structures, which can occur when theloop material is spooled or when the finished product to which the loopmaterial is later joined is compressed for packaging. Stiff papers donot tend to form the lip shown protruding about the trunk 43 of theformation. Resiliency of the trunk 43, especially at its juncture withthe base, enables structures 48 that have been “toppled” by heavy crushloads to right themselves when the load is removed. The various loops 40of formation 48 extend to different heights from the paper, which isalso believed to promote fastener performance. Because each formation 48is formed at a site of a penetration of paper 14 during needling, thedensity and location of the individual structures are very controllable.Preferably, there is sufficient distance between adjacent structures soas to enable good penetration of the field of formations by a field ofmating male fastener elements (not shown). Each of the loops 40 is of astaple fiber whose ends are disposed on the opposite side of the carriersheet, such that the loops are each structurally capable of hookengagement. One of the loops 40 in this view is shown as being of abicomponent fiber 41. After laminating, the paper and fibers becomepermanently bonded together at discrete points 42 corresponding to thedistal ends of pins 20.

Because of the relatively low amount of fibers remaining in the mat,together with the thinness of the carrier sheet and any applied backinglayer, mat 108 can have a thickness “t_(m)” of only about 0.008 inch(0.2 millimeters) or less, preferably less than about 0.005 inch, andeven as low as about 0.001 inch (0.025 millimeter) in some cases. Thecarrier may 14 have a thickness of less than about 0.002 inch (0.05millimeter), preferably less than about 0.001 inch (0.025 millimeter).The finished loop product 30 has an overall thickness “T” of less thanabout 0.15 inch (3.7 millimeters), preferably less than about 0.1 inch(2.5 millimeters). The overall weight of the loop fastener product,including carrier sheet, fibers and fused binder (an optional component,discussed below), is preferably less than about 5 ounces per square yard(167 grams per square meter). For some applications, the overall weightis less than about 2 ounces per square yard (67 grams per square meter).

FIG. 4A is an enlarged photograph of a loop product formed by needlingfibers through a film with fork needles. The view is taken toward afolded edge of the product, so as to spread out the loop structures forincreased visibility. Five of the loop structures shown in thephotograph have been marked with an ‘X’. The surface of the film isclearly visible between the loop structures, each of which contains manyindividual loops emanating from a common trunk, as shown in FIG. 4B, anenlarged view of a single one of the loop structures. In FIG. 4B, lightis clearly seen reflected at the base of the loop structure from filmthat has been raised about the hole during piercing. An outline of theraised portion of film is shown on the photograph.

Needling papers of rather high notch sensitivity or tendency to tear cancreate loop structures of the sort shown in FIG. 4C. In this case, thepaper about the hole created by a needle doesn't tend to create the‘turtleneck’ effect as in FIG. 4, with the result that the fiberspassing through the paper may be not as securely supported againstcrushing. Well-supported loop trees are more able to resist crushing,such as from spooling of the loop material, than less-supported bushstructures.

Referring next to FIG. 5, in an alternative lamination step a powderedbinder 46 is deposited over the fiber side of the needle-punched paperand then fused to the paper by roll 28 or a flatbed laminator. Forexample, a polyethylene powder with a nominal particle size of about 20microns can be sprinkled over the fiber-layered paper in a distributionof only about 0.5 ounces per square yard (17 grams per square meter).Such powder is available in either a ground, irregular shape or agenerally spherical form from Equistar Chemicals LP in Houston, Tex..Preferably, the powder form and particle size are selected to enable thepowder to sift into interstices between the fibers and contact theunderlying paper. It is also preferable, for many applications, that thepowder be of a material with a lower melt temperature than the loopfibers, such that during bonding the fibers remain generally intact andthe powder binder fuses to either the fibers or the carrier web. Ineither case, the powder acts to mechanically bind the fibers to thepaper in the vicinity of the supporting pins and anchor the loopstructures. In sufficient quantity, powder 46 can also form at least apartial backing in the finished loop product, for permanently bondingthe loop material onto a compatible substrate. Other powder materials,such as polypropylene or an EVA resin, may also be employed for thispurpose, with appropriate carrier web materials, as can mixtures ofdifferent powders.

Referring back to FIG. 1, in some cases the needling parameters (e.g.,needle size, needling density) can be selected to cause the carrier web14 to be practically disintegrated during needling. While this isundesirable for some applications, we have found that such a structureis advantageous for other uses. FIG. 6 illustrates a resultingstructure, in which the fibers 12 themselves form practically the onlyconnectivity within the needled sheet. The paper itself remains in theform of discrete portions 69 separated by cracks 67 extending betweenadjacent loop trunks 43. This structure is sufficiently dimensionallystable to be laminated to a stretchable backing film, such as apolypropylene or polyethylene film available from Tredegar Film Productsin Richmond, Va.. During lamination, the discrete segments 66 of carrierpaper may bond to the stretchable backing, further anchoring the basesof the loop structures while permitting the final loop product to beelastically stretchable within its plane.

A pre-printed paper may be employed as the carrier web to providegraphic images visible from one or both sides of the finished product.The small bonding spots and the low density of fiber remaining in themat generally do not significantly detract from the visibility of theimage. This can be advantageous, for example, for loop materials to beused on children's products, such as disposable diapers, or inpackaging.

FIG. 7 shows a finished loop product, as seen from the loop side,embossed with a honeycomb pattern 58. In this example, graphic images130 printed on the back side of the carrier (in this case, a film) areclearly visible through the loops. Various other embossing patternsinclude, as examples, a grid of intersecting lines forming squares ordiamonds, or a pattern that crushes the loop formations other than indiscrete regions of a desired shape, such as round pads of loops. Theembossing pattern may also crush the loops to form a desired image, ortext, on the loop material. As shown in FIG. 7A, each cell of theembossing pattern is a closed hexagon and contains multiple discreteloop structures. The width ‘W’ between opposite sides of the open areaof the cell is about 6.5 millimeters, while the thickness ‘t’ of thewall of the cell is about 0.8 millimeter.

Referring to FIG. 8, in one method of forming a product with onlydiscrete regions of loop the fiber-covered carrier web is needled onlyin desired regions, leaving other areas of the web unpenetrated. Thefibers in the non-needled regions remain generally loose and are readilyremoved from the carrier web, such as by vacuum 110. Removed fibers arereadily re-carded and thus recycled. The needled web is then optionallylaminated to a backing 26, fusing to the carrier sheet in thefiber-covered and needled regions as well as in the fiber-free regions.Alternatively, the fibers are fused to each other and/or the carriersheet under pressure applied by hot can 28, without an added backinglayer. The laminate product is then spooled for later use.

In the alternative bonding process illustrated in FIG. 9, discretepatches of backing 26 are applied to cover the needled and fiber-bearingregions of carrier web 14, leaving the remaining regions of the carrierweb uncovered and unlaminated. Each backing patch 26 is bonded in placeby pressure from roller 112 to cover the fibers remaining on the backsurface of the carrier web. Fluid impermeable patches 26 can be employedto seal the needled holes, thereby creating a fluid-impermeable finishedproduct of particularly low weight and nominal thickness. In some cases,paper backing patches 26 are pre-coated with an adhesive that adheresthe backing to the carrier paper and bonds the fibers. Patches 26 can bedelivered to carrier 14 on a circulating conveyor belt 114 in a labelingprocess, as shown.

If the needled regions of the loop product are covered with a backingmaterial 26 selected to be liquid impermeable, then the entire loopproduct can be formed to provide a barrier to liquids. If fibers 12 areselected to be absorbent, such as of cotton or cellulosic acetate, thenthe final loop product can be employed to wick liquids into the mat viathe exposed loops 40.

The above-described processes enable the cost-effective production ofhigh volumes of loop-covered paper materials with good fasteningcharacteristics. They can also be employed to produce loop materials inwhich the materials of the loops, substrate and optional backing areindividually selected for optimal qualities. For example, the loop fibermaterial can be selected to have high tenacity for fastening strength,while the paper substrate and/or backing material can be selected to bereadily bonded to other materials without harming the loop fibers.

The carrier web can be a solid or a very porous sheet of paper, and canbe, for example, very soft paper such tissue paper (bathroom or facialtissue, for example), stronger papers such as Kraft paper (made byadding sodium sulfate to the soda process in paper making), disposablepaper towels, typing paper, newsprint stock, or “construction” paper.The paper carrier web may be pre-pasted with an adhesive on the fiberside to help bond the fibers and/or a backing layer to the paper.Heavier papers may require larger needles for piercing, which may bearranged in a lower needle density on the needle board to reduceneedling loads. The needles may also need to be checked more frequentlyfor wear caused by abrasion from the paper.

Biodegradable loop products can be made from paper into whichbiodegradable fibers are needled. Such fibers that have sufficienttenacity to form loops include, for example, polyvinyl alcohol (PVA) andpolylactic acid fibers.

Polymer backing layers or binders may be selected from among suitablepolyethylenes, polyesters, EVA, polypropylenes, and their co-polymers.Paper, fabric or even metal may be used. The binder may be applied inliquid or powder form, and may even be pre-coated on the fiber side ofthe carrier web before the fibers are applied. In many cases, a separatebinder or backing layer is not required, such as for low cycleapplications.

FIG. 10 shows a loop product 300 consisting essentially of a sheet ofpaper 302 and fibers that have been needled through the paper from backside 304, as described above, to form discrete loop structures 48 on thefront side. The needled, fiber-punched paper is laminated with cardcloth as discussed above with respect to FIG. 1, such that fibers onback side 304 are bonded to each other at discrete points, withoutforming an overly stiff backing. We have found that some types of paperremain quite dimensionally stable and cohesive through needling, suchthat the paper substrate may, in many cases, provide a surface suitablefor bonding to film or other substrates, such as with adhesives. Thebonded web of fibers remaining on the back can be heated to form anadhesive for bonding the paper to another material, such as polyethylenefilm, or a separate adhesive may be applied.

In one example, the product 300 of FIG. 10 is a towel for generalpurpose cleaning, and is formed from a standard paper towel into whichPVA fibers have been needled. The resulting product is less susceptibleto disintegration when wet than the un-needled paper towel, as the PVAfibers tend to provide dimensional stability as the paper substrateloses strength when wet. Thus, the product is more capable of performingcleaning functions in a wet state, but remains disposable andbiodegradable.

In another example, the product 300 of FIG. 10 is a scrubbing sheetmaterial, consisting essentially of a paper substrate 302 into whichemery fibers have been needled according to the methods discussed above.The paper provides a carrier sheet for the emery fibers duringmanufacture, such that less such expensive fibers are required than inscrubbing products formed by needling a thick batt of such fibers.Furthermore, the surface structure of discrete, spaced apart loopstructures is considered to be particularly suitable for scrubbing.

In another example, the product 300 of FIG. 10 is a backing material foran abrasive disk, which may be formed by bonding abrasive particles (notshown) to the back side 304 of the product, such that loop structures 48extend from the side opposite the abrasive particles and can serve toreleasably attach the abrasive disk or sheet to a holder, such as anelectric sander. Referring also to FIG. 13, a sanding disk or sandpaper320 has an array of engageable loop structures 48 formed by needlingpolymer fibers through a sheet 14 of paper, leaving a thin layer offibers on the opposite side of the paper, and then bonding a field ofabrasive particles 322, such as silica or other hard material, on theother side.

In another example, the product 300 of FIG. 10 is an abrasive sheet,consisting essentially of steel wool fibers or other hard fibers needledthrough paper or another carrier. As in the previous examples, employingthe paper substrate to carry the loose fibers prior to and duringneedling enables the use of fewer expensive fibers, resulting in a costeffective product with consistently formed loop structures 48 spacedabout on the surface of the product where their properties are mostneeded. Such constructions also result in usefully thin and flexibleproducts. Referring also to FIG. 14, a sanding material 324 has a papersubstrate 14 through which staple steel wool fibers have been needled toform loop structures 48. Steel wool fibers 326 remaining on the oppositesurface of the paper form an abrasive working surface 328, while theloop structures releasably secure material 324 to a carrier.

In another example, the product 300 of FIG. 10 is a fastener product,with loop structures 48 configured for hook engagement to form a touchfastener, using the loop fiber materials discussed above. Variousapplications of such a paper-based loop material are envisioned. Forexample, in FIG. 11 a piece of unbleached, uncoated paper has beenneedled with polyethylene stable fibers and laminated to bond the fibersas discussed above. A pleated paper core 308 is then sandwiched betweenthe resulting sheet-form loop-covered paper product 300 and anothersheet 310 of paper, to form a corrugated cardboard 312. Such cardboardcan be formed into boxes, displays or other structures, with loopproduct 300 covering an exposed surface for mounting hook-bearing papersor products.

In another example shown in FIG. 12, multiple sheets of loop-bearingpaper 300 are bound together to form a photo album or scrapbook 314, inwhich hook-backed photos 316 or other memorabilia are releasably securedby engagement of their hooks with the loop structures of paper 300. Forthis application, the fibers remaining on the back side of the paper mayprovide sufficient fastening performance to mount such photos on theopposite sides of the paper, as well. Hook-backed photo paper and itsmethod of manufacture are disclosed in a PCT application published Mar.4, 2004, as WO04/017781. Other uses and constructions of loop-coveredpaper products are disclosed in pending U.S. application Ser. No.10/657,507, the entire contents of which are hereby incorporated byreference.

The carrier sheets in the specific examples discussed above may bematerials other than paper.

Paper substrates may be pre-printed with desired graphics, either on oneor both sides, prior to needling.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method of making a sheet-form loop fastener product, the methodcomprising placing a layer of staple fibers against a first side of aflexible paper substrate; needling fibers of the layer through the papersubstrate by piercing the substrate with needles that drag portions ofthe fibers through holes formed in the paper substrate during needling,forming loops of the fibers extending from the holes on a second side ofthe paper substrate; selecting needling parameters so that the loopshave a size and structure selected to engage a field of correspondingmale fastener elements; and anchoring fibers forming the loopssufficiently to resist pull-out loads caused by releasable engagementwith the male fastener elements.
 2. The method of claim 1 wherein thefibers include bicomponent fibers having a core of one material and asheath of another material, and wherein anchoring the fibers comprisesmelting material of the sheaths of the bicomponent fibers to bind fiberstogether.
 3. The method of claim 1 wherein needling fibers of the layerthrough the paper substrate and anchoring fibers forming the loops formsloops sized and constructed to be releasably engageable by a field ofhooks for hook-and-loop fastening.
 4. The method of claim 1 wherein thestaple fibers are disposed on the substrate in a layer of a total fiberweight of less than about 2 ounces per square yard (67 grams per squaremeter).
 5. The method of claim 4 wherein the staple fibers are disposedon the substrate in a layer of a total fiber weight of no more thanabout one ounce per square yard (34 grams per square meter).
 6. Themethod of claim 1 wherein the staple fibers are disposed on thesubstrate in a carded, unbonded state.
 7. The method of claim 1 furthercomprising, prior to disposing the fibers on the substrate, carding andcross-lapping the fibers.
 8. The method of claim 1 wherein the loopproduct has an overall weight of less than about 5 ounces per squareyard (167 grams per square meter).
 9. The method of claim 1 whereinanchoring occurs subsequent to needling.